From a3a21ecd375ce146d28d19f083e560bbbe739d91 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=A1=D0=B5=D1=80=D0=B3=D0=B5=D0=B9=20=D0=9F=D1=80=D0=BE?=
 =?UTF-8?q?=D1=85=D0=BE=D1=80=D0=BE=D0=B2?= <seriy.pr@gmail.com>
Date: Thu, 7 Mar 2019 02:30:02 +0100
Subject: [PATCH] Make it possible to configure upstream healthchecks

---
 src/mtp_handler.erl       | 23 +++++++++++++----------
 src/mtproto_proxy.app.src |  7 +++++++
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/mtp_handler.erl b/src/mtp_handler.erl
index c660352..71a48ba 100644
--- a/src/mtp_handler.erl
+++ b/src/mtp_handler.erl
@@ -345,28 +345,31 @@ maybe_check_health(#state{last_queue_check = LastCheck} = S) ->
             end
     end.
 
-%% 1. If proc queue > 300 - stop
-%% 2. If proc total memory > 400kb - do GC and go to 3
-%% 3. If proc total memory > 4mb - stop
+%% 1. If proc queue > qlen - stop
+%% 2. If proc total memory > gc - do GC and go to 3
+%% 3. If proc total memory > total_mem - stop
 check_health() ->
-    do_check_health([qlen, gc, total_mem], calc_health()).
+    %% see .app.src
+    Defaults = [{qlen, 300},
+                {gc, 409600},
+                {total_mem, 3145728}],
+    Checks = application:get_env(?APP, upstream_healthchecks, Defaults),
+    do_check_health(Checks, calc_health()).
 
-do_check_health([qlen | _], #{message_queue_len := QLen} = Health) when
-      QLen > ?HEALTH_CHECK_MAX_QLEN ->
+do_check_health([{qlen, Limit} | _], #{message_queue_len := QLen} = Health) when QLen > Limit ->
     mtp_metric:count_inc([?APP, healthcheck, total], 1,
                          #{labels => [message_queue_len]}),
     lager:warning("Upstream too large queue_len=~w, health=~p", [QLen, Health]),
     overflow;
-do_check_health([gc | Other], #{total_mem := TotalMem}) when
-      TotalMem > ?HEALTH_CHECK_GC ->
+do_check_health([{gc, Limit} | Other], #{total_mem := TotalMem}) when TotalMem > Limit ->
     %% Maybe it doesn't makes sense to do GC if queue len is more than, eg, 50?
     %% In this case allmost all memory will be in msg queue
     mtp_metric:count_inc([?APP, healthcheck, total], 1,
                          #{labels => [force_gc]}),
     erlang:garbage_collect(self()),
     do_check_health(Other, calc_health());
-do_check_health([total_mem | _Other], #{total_mem := TotalMem} = Health) when
-      TotalMem > ?HEALTH_CHECK_MAX_MEM ->
+do_check_health([{total_mem, Limit} | _Other], #{total_mem := TotalMem} = Health) when
+      TotalMem > Limit ->
     mtp_metric:count_inc([?APP, healthcheck, total], 1,
                          #{labels => [total_memory]}),
     lager:warning("Process too large total_mem=~p, health=~p",
diff --git a/src/mtproto_proxy.app.src b/src/mtproto_proxy.app.src
index f7ee4af..22e0321 100644
--- a/src/mtproto_proxy.app.src
+++ b/src/mtproto_proxy.app.src
@@ -74,6 +74,13 @@
         %% Mostly used to testing
         %% {proxy_secret_url, "https://core.telegram.org/getProxySecret"},
         %% {proxy_config_url, "https://core.telegram.org/getProxyConfig"},
+
+        %% Upstream self-healthchecks tuning
+        %% {upstream_healthchecks,
+        %%  [{qlen, 300},         % if queue length >X - close connection
+        %%   {gc, 409600},        % if connection memory >X - do garbage collection
+        %%   {total_mem, 3145728} % if connection memory >X - close connection
+        %%  ]},
        ]},
   {modules, []},